CMake政策的范围是什么？ [英] What is the scope of CMake policies?

问题描述

我有一个带有多个子目录的CMake项目，例如：

I've got a CMake project with several subdirectories, like this one:

dir1
    subdir11
    subdir12
dir2
    subdir21
    subdir22

根CMakeLists。 txt：

Root CMakeLists.txt:

add_subdirectory(dir1)
add_subdirectory(dir2)

CMake dir1和dir2中的列表类似：

CMakeLists in dir1 and dir2 are similar:

add_subdirectory(subdir11)
add_subdirectory(subdir12)

和

add_subdirectory(subdir21)
add_subdirectory(subdir22)

子目录中的CMakeLists会进行实际工作。

And CMakeLists in subdirs do actual work.

文件 dir1 / subdir12 / CMakeLists.txt 将 CMP0046 策略设置为 OLD ：

cmake_policy(SET CMP0046 OLD) #silently ignore missing dependencies

我的问题是-CMP0046的此设置是否传播到 subdir21 和 subdir22 吗？

My question is - will this setting of CMP0046 propagate to subdir21 and subdir22 ?

推荐答案

没有从文档中直接 可以最好地回答这个问题 ...

No. This question is best answered straight from the documentation...

策略设置使用堆栈作用域。进入项目的新子目录（带有
add_subdirectory）时，将压入
堆栈的新级别，并在退出时弹出该堆栈。因此，在项目的一个目录中设置
策略不会影响父目录或同级
目录，但会影响子目录。

Policy settings are scoped using a stack. A new level of the stack is pushed when entering a new subdirectory of the project (with add_subdirectory) and popped when leaving it. Therefore setting a policy in one directory of a project will not affect parent or sibling directories but will affect subdirectories.

要在不包含子目录的情况下对特定级别进行临时更改，可以使用

For making temporary changes to a specific level, without including sub_directories, you can use

cmake_policy(PUSH)
cmake_policy(POP)

如果要将策略应用于subdir21和subdir22，则需要添加它在那里，或考虑将其添加到公共父级。

If you want the policy applied in subdir21 and subdir22 you either need to add it there explicitly or consider adding it to the common parent.

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